In the German patent DE 199 22 961 C2 an emission control system for the purification of the exhaust gas of a combustion source, especially the internal combustion engine of a motor vehicle, is described at least by the nitrogen oxides contained therein with an ammonia producing catalytic converter for the production of ammonia using components of at least one part of the exhaust gas emitted from the combustion source during the ammonia producing operational phases and with a nitrogen oxide reduction catalytic converter subsequently connected to the ammonia production catalytic converter for the reduction of the nitrogen oxides contained in the exhaust gas emitted from the combustion source using the ammonia produced as a reducing agent. Provision is made thereby for a nitrogen oxide production unit external to the combustion source for the enrichment of the exhaust gas supplied to the ammonia production catalytic converter with the nitrogen oxide it produces during the ammonia producing operational phases. A plasma generator is proposed, for example, as a nitrogen oxide production unit for the plasma engineered oxidation of the nitrogen contained in a gas stream, which is supplied, to nitrogen oxide. The hydrogen required for the ammonia production is produced during the ammonia production operational phases by the operation of the combustion source with a rich, i.e. fuel rich air ratio.
A plasma chemical procedure to produce a hydrogen rich gas mixture is described in the patent WO 01/14702 A1. With the procedure, a rich fuel-air-mixture is dealt with in an arc, preferably under POx conditions.
In order to avoid the transport of an additional resource, a plasma procedure was proposed by the applicant in a still unpublished writing for the on-board-generation of reducing agents. In so doing, necessary ammonia from non-toxic substances are produced according to need in the vehicle and subsequently supplied to the SCR-process. An acceptable solution with regard to the fuel consumption is afforded thereby by an intermittently operated procedure for ammonia production, which likewise is proposed in this writing. This procedure is denoted as follows as the RGS-procedure (Reductant Generating System) or the reducing agent generating system.
A disadvantage of this procedure is that especially in the starting phase the reducing agent generation system (RGS) only very slowly achieves an adequately high operating temperature, at which an optimal functionality is guaranteed. The strategy up to the present makes provision for a burner functionality, which makes possible for the system to be made operational, especially the catalytic components for partial oxidation at approximately 500E C and the ammonia production unit at approximately 250E C. For that purpose, provision is made for a diesel fuel combustion in a flame to be contingently supported by a catalytic combustion within the catalytic components.
A disadvantage is that an additional mechanism is required to heat the reducing agent generation system (RGS) up to full operating status.
It is therefore the task of the invention to provide a procedure, in which on the one hand allows for the quick achievement of an optimal operating temperature of the RGS-unit and on the other hand minimizes the expenditure for auxiliary mechanisms. It is furthermore the task of the invention, to provide at this point a suitable device.